The present invention relates to a biodegradable organic growth composition which is based on particulate coal.
The plant growth composition of the invention represents an improvement in the formulation described in U.S. Pat. No. 4,541,857, the contents of which are incorporated herein by reference.
U.S. Pat. No. 4,541,857 describes a plant fertilizer composition which comprises a mixture of particulate coal containing releasable plant nutrients, sodium molybdate which serves to release the plant nutrients in a form that plants can use, and one or more auxiliary agents selected from ferric sulfate, magnesium sulfate, sodium chloride, zinc sulfate, zinc chloride, copper sulfate, sulfur, hydrated sodium borate, brunt limestone and cobalt carbonate. The coal particulate has a maximum mesh size of about 100 mesh and comprises from about 50-75 weight percent of the total weight of the composition, the molybdate is present in an amount ranging from 0.001 to 0.100 percent by weight of the composition and the auxiliary agent(s) comprise the balance of the composition.
As indicated, the present invention provides certain improvements in the compositions described in U.S. Pat. No. 4,541,857. These improvements maintain the useful features of the composition described in the earlier patent but also result in further advantages as detailed hereinafter, including, for example, enhanced growth and yield of plants and expanded applicability and use of the composition.
An important modification in the compositions of U.S. Pat. No. 4,541,857 which the present invention provides is the use of a linear alcohol alkoxylate, e.g. a poly(ethylene oxide) ether with a C12-C15 linear primary alcohol.
Other essential features of the present composition include the use of a substantial amount of sand and a small amount of water. Further features will also be evident from the more detailed description of the invention which follows.
The plant growth composition of the invention consists essentially of the following components:
(1) 40-80%, preferably 70-80%, by weight of particulate coal;
(2) 0.01 to 1%, preferably 0.5 to 1%, by weight of sodium molybdate;
(3) from 0.2 to 2% by weight water;
(4) from 0.1 to 1% by weight of linear alcohol alkoxylate;
(5) from 0.001 to 4% by weight of magnesium sulfate; with
(6) the balance, usually in an amount of about 20-60% by weight of the overall composition, being sand.
The composition thus consists primarily of coal and sand in its preferred embodiment although molybdate, linear alcohol alkoxylate, magnesium sulfate and water, within the limits indicated, are also essential for the success of the invention.
Of the indicated components, the coal particulate is advantageously as described in the earlier U.S. Pat. No. 4,541,857 referred to above. Thus, the coal particulate may be of any type, for instance, anthracite, bituminous, sub-bituminous or lignite, and can be of varying quality all of which generally contain from about 0.5 to 3.0 percent of known nitrogen. Other plant nutrients present in coal and made available for use by plants in accordance with the present invention include iron, phosphorus, potassium, sulfur or sulfates, calcium, chloride and at least traces of manganese, copper, boron, cobalt, alumina and selenium. High sulfur content coal has been found to be particularly advantageous.
Advantageously, the coal is of 100 mesh particulate size or smaller, i.e. it is such that it passes through a 100 mesh Tyler Screen. Larger and smaller sizes can be effectively used ranging from, for example, xe2x88x9250 mesh to about xe2x88x92300 mesh. Particles larger than 100 mesh, however, tend to release plant nutrients more slowly. Hence, it is preferred to use a coal particulate of 100 mesh size or finer, i.e. particles which will pass through a 100 mesh Tyler Screen.
While any type of coal can be used, preferably one of high sulfur content, the coal composition specifically exemplified in U.S. Pat. No. 4,541,857 may be cited as typical for use herein. Such coal, on a dry basis, has the following ultimate analysis:
As explained in U.S. Pat. No. 4,541,857, the sodium molybdate appears to function in some way to digest the coal particulate and to release plant nutrients from the particulate in a way which enables plants to effectively and advantageously use these nutrients. While the amount of molybdate can be varied and may in some instances fall outside the ranges earlier stated, depending on the nature and size of the coal particulate, best results appear to be obtainable when the molybdate content is in the range of 0.5-1% by weight of the total composition. More than this preferred amount can be used although it is believed that effective digestion of the coal is realized by using the molybdate in the amount indicated.
The linear alcohol alkoxylate is preferably a primary linear C12 to C15 alcohol, e.g. dodecyl alcohol or mixture thereof with other C12-C15 alcohol, which has been ethoxylated, i.e. a polyethylene oxide ether of a primary linear alcohol, preferably a primary alcohol of 12-15 carbons. A preferred linear alcohol alkoxylate for use herein is available commercially as xe2x80x9cBasic Hxe2x80x9d surfactant. This material, or its equivalent, may be used for present purposes.
As indicated, the composition should also contain a small amount of water, usually not more than about 2% by weight. It appears that this small amount of water facilitates the effect of the alkoxylate and also seems to help activate the plant growth elements of the coal component.
Any convenient source of sand may be used. The amount of sand employed can be varied and will depend, at least to some extent, on the nature and composition of the coal component, and the amounts of other materials present. However, generally speaking, the amount of sand in the composition will fall within the range earlier stated herein, i.e. 20-60% by weight.
Optimum results appear to be obtained with sand which includes small amounts, e.g. 0.001 to 0.01% by weight, of magnesium sulfate, copper sulfate and other similar trace metal sulfates.
In addition to any magnesium sulfate which may be included in the sand, it is useful to add magnesium sulfate in an amount of from 0.001 to 4% by weight of the composition.
The composition may be prepared in any convenient fashion. Preferably, however, the coal and sand are uniformly mixed together after which the sodium molybdate, alkoxylate and magnesium sulfate, in water are sprayed over the coal/sand mixture while stirring to insure uniformity. The product is then allowed to dry after which it may be bagged for later use or applied directly to the soil at the place of use.
As an alternative, the mixture of coal and sand may be placed at the site of use, e.g. around the base of a fruit tree, after which an aqueous mix of molybdate and alkoxylate is sprayed over the coal/sand mix. The magnesium sulfate may be included in the aqueous spray of alkoxylate and molybdate or it may be included in the coal/sand mix.
In a typical preparation, 1 to 4 ounces of sodium molybdate and up to 1 gallon of the alkoxylate, with or without magnesium sulfate, are mixed with 50 gallons, more or less, of water to form a spray mixture. This mixture is then sprayed over a dry mix of coal particulate and sand and magnesium sulfate. Advantageously the mixture of molybdate and alkoxylate in water is sprayed over a dry mix of coal, sand and magnesium sulfate after the dry mix has been applied to the field or soil where plant growth is desired although, as earlier noted, the entire composition, including the molybdate and alkoxylate, can be prepared before application to the field or soil. Whether pre-formed or prepared in situ, it appears that the spray of molybdate and alkoxylate helps to activate the nutrients or growth elements in the coal.
The composition of the invention is usable under most, if not all, soil conditions globally. An important advantage of the invention, as shown below, is that the composition appears to be able to convert soil which is unsatisfactory for agricultural purposes into soil which is highly useful. In extensive testing, the product has consistently exceeded yield by 50-100% per acre production as measured against conventionally available Nxe2x80x94Pxe2x80x94K fertilizers which are in common usage.
The invention is illustrated by the following examples: